BLACK HOLES EXPLAINED - FROM BIRTH TO DEATH

BLACK HOLES EXPLAINED - FROM BIRTH TO DEATH 

Black holes are one of the strangest things in existence. They don't seem to make any sense at all. Where do they come from and what happens if you fall into one ?

Stars are incredibly massive collections of mostly Hydrogen atoms that collasped from enormous gas clouds under their own gravity. In their core, nucleur fusion crushes Hydrogen into helium releasing a tremendous amount of energy. This energy, in the form of radiation, pushes against gravity, maintaining a delicate balance between the two forces. As long as there is fusion in the core, the stars remain stable enough. But for stars with way more mass than our own sun , the heat and pressure at the core allow them to fuse heavier elements until they reach iron. Unlike all the elements that went before, the fusion process that creates iron doesnot generate any energy. 

Iron builds up at the centre of the star until it reaches a critical amount and the balance between radiation and gravity is suddenly broken. The core collapses. Within a fraction of second, the star explodes. Moving at about the quater of the speed of light, feeding more mass into the core.  It's at this very moment that all the heavy elements in the universe are created, as the star dies, in a supernova explosion. This produces either a neutron star, or if the star is massive enough, the entire mass of core collapses into a black hole. If you looked at a black hole, what you'd really be seeing is the even horizon.

Anything that crosses the event horizon needs to be travelling faster than speed of light to escape. In other words, it's impossible. So we just see a black sphere reflecting nothing but if the event horizon is the black part, What is the "hole" part of the black hole ? The Singularity. We are not actually sure what it is exactly. A singularity may be infinitely dense, meanimg all it's mass is concentrated into a singke point in space, with no surface or volume, or something completely different. Right now, we just don't know. It's like a "dividing by 0" error. By the way, black holes donot such things up like a vaccum cleaner, If we were to swap the sun for an equally massive black hole, nothing much would change for earth, except that we would freeze to death, of course. 

What would happen to you if you fell into a black hole ? 

The experience of time is different around black holes, from the outside, you seem to slow down as you approach the event horizon, so time passes slower for you. At some point, you would appear to freeze in time, slowly turn read, and disappear. While from your prospective, you can watch the rest of the universe in fast forward, kind of like seeing into the future. Right now, we don't knkw what happens next, but it could be one of the two things:

• One, you die a quick death. A black hole curves your space so much, that once yoh cross the even horizon, there is only one possible direction. It's like being in a really tight alley that closes behind you after each step. The mass of the black hole is some much that at some time even tiny distance of a few centimetres, would mean that gravity acts with millions of times more force on different parts of your body. Your cells gets torn apart, as your body stretches more and more, until you are a hot stream of plasma, one atom wide. 
• Two, you die a very quick death. Very soon after you cross the event horizon, You would hit a firewall and be terminated in an instant. 

           Neither of this options are particularly pleasant. How soon you die depends on the mass of the black hole. A smaller black hole would kill you even before you hit the event horizon, while you probably could travel inside a super massive black hole for quite a while. As a rule of thumb, the further away from the singularity you are, the longer you live.

   Black holes comes in different sizes. There are steller mass black holes, with a few times the mass of the sun, and tge diameter of an asteroid. And then there are the super massive black holes, which are found at the heart of every galaxy, an have been feeding for billions of years. Currently, the largest super massive black hole known, is 

S5 0014+81. 40 billion times the mass of our sun. It is 236.7 billion kilimeters in diameter, which is 47 times the distance from sun to pluto. As powerful as black holes are, they will eventually evaporate through a process called Hawking radiation. To understand how this works, we have to look at the empty space. Empty space is not really empty but filled with virtual particles popping into existence and annihilating each other again. When this happens right on the edge of black hole, one of the particles woukd be drawn into the black and other will escape and become real particle.

So the black hole is losing energy. This happens incredibly slowly at first, and gets faster as the black hole becomes smaller. When it arriaves at the mass of a large asteroid, It's radiating at room temperature. When it has the mass of a mountain, it radiates with about the heat of our sun. And in the last second of it's life, the black hole radiates away with the energy of billions of nucleur bomb in a huge explosion. But this process is incredibly. The black holes we know, might take up a googol year to evaporate. This is so long that when the last black holes radiates away, nobody will be around to witness it. The universe will have become uninhavitable, long before then. This is not the end of our story, there are loads more interesting ideas about the black holes, we will explore them in part 2. 

Please tell me in the comment section if you enjoyed reading about it and you are really eager for part 2.